Research work to understand the mechanism of LH/hCG binding to particulate receptors of rat testes and to ascertain the role of soluble factors in modulation of the gonadotropin binding is in progress. Purification and characterization of LH/hCG specific factor, its relationship with membrane receptor and adenylate cyclase will be essential in understanding the molecular events that lead to or regulated by hormone initiated cellular events. BIBLIOGRAPHIC REFERENCES: Gonadotropin Binding Factors: Extraction of high affinity gonadotropin binding sites from rat testes and partial characterization of their interaction with human follitropin, lutropin and choriogonadotropin. Vinod K. Bhalla, J. Haskell, H. Grier and V. B. Mahesh, J. Biol. Chem. 251:4947-4957, 1976.